MANDOC(3) BSD Library Functions Manual MANDOC(3)NAME
mandoc, mandoc_escape, man_meta, man_mparse, man_node, mchars_alloc,
mchars_free, mchars_num2char, mchars_num2uc, mchars_spec2cp,
mchars_spec2str, mdoc_meta, mdoc_node, mparse_alloc, mparse_free,
mparse_getkeep, mparse_keep, mparse_readfd, mparse_reset, mparse_result,
mparse_strerror, mparse_strlevel — mandoc macro compiler library
LIBRARY
library “mandoc”
SYNOPSIS
#include <man.h>
#include <mdoc.h>
#include <mandoc.h>
enum mandoc_esc
mandoc_escape(const char **end, const char **start, int *sz);
const struct man_meta *
man_meta(const struct man *man);
const struct mparse *
man_mparse(const struct man *man);
const struct man_node *
man_node(const struct man *man);
struct mchars *
mchars_alloc();
void
mchars_free(struct mchars *p);
char
mchars_num2char(const char *cp, size_t sz);
int
mchars_num2uc(const char *cp, size_t sz);
const char *
mchars_spec2str(const struct mchars *p, const char *cp, size_t sz,
size_t *rsz);
int
mchars_spec2cp(const struct mchars *p, const char *cp, size_t sz
const char * );
const struct mdoc_meta *
mdoc_meta(const struct mdoc *mdoc);
const struct mdoc_node *
mdoc_node(const struct mdoc *mdoc);
void
mparse_alloc(enum mparset type, enum mandoclevel wlevel, mandocmsg msg,
void *msgarg);
void
mparse_free(struct mparse *parse);
void
mparse_getkeep(const struct mparse *parse);
void
mparse_keep(struct mparse *parse);
enum mandoclevel
mparse_readfd(struct mparse *parse, int fd, const char *fname);
void
mparse_reset(struct mparse *parse);
void
mparse_result(struct mparse *parse, struct mdoc **mdoc,
struct man **man);
const char *
mparse_strerror(enum mandocerr);
const char *
mparse_strlevel(enum mandoclevel);
extern const char * const * man_macronames;
extern const char * const * mdoc_argnames;
extern const char * const * mdoc_macronames;
#define ASCII_NBRSP
#define ASCII_HYPH
DESCRIPTION
The mandoc library parses a UNIX manual into an abstract syntax tree
(AST). UNIX manuals are composed of mdoc(7) or man(7), and may be mixed
with roff(7), tbl(7), and eqn(7) invocations.
The following describes a general parse sequence:
1. initiate a parsing sequence with mparse_alloc();
2. parse files or file descriptors with mparse_readfd();
3. retrieve a parsed syntax tree, if the parse was successful, with
mparse_result();
4. iterate over parse nodes with mdoc_node() or man_node();
5. free all allocated memory with mparse_free(), or invoke
mparse_reset() and parse new files.
The mandoc library also contains routines for translating character
strings into glyphs (see mchars_alloc()) and parsing escape sequences
from strings (see mandoc_escape()).
REFERENCE
This section documents the functions, types, and variables available via
<mandoc.h>.
Types
enum mandoc_esc
An escape sequence classification.
enum mandocerr
A fatal error, error, or warning message during parsing.
enum mandoclevel
A classification of an enum mandoclevel as regards system operation.
struct mchars
An opaque pointer to an object allowing for translation between character
strings and glyphs. See mchars_alloc().
enum mparset
The type of parser when reading input. This should usually be
MPARSE_AUTO for auto-detection.
struct mparse
An opaque pointer to a running parse sequence. Created with
mparse_alloc() and freed with mparse_free(). This may be used across
parsed input if mparse_reset() is called between parses.
mandocmsg
A prototype for a function to handle fatal error, error, and warning mes‐
sages emitted by the parser.
Functions
mandoc_escape()
Scan an escape sequence, i.e., a character string beginning with ‘\’.
Pass a pointer to the character after the ‘\’ as end; it will be set to
the supremum of the parsed escape sequence unless returning ESCAPE_ERROR,
in which case the string is bogus and should be thrown away. If not
ESCAPE_ERROR or ESCAPE_IGNORE, start is set to the first relevant charac‐
ter of the substring (font, glyph, whatever) of length sz. Both start
and sz may be NULL.
man_meta()
Obtain the meta-data of a successful parse. This may only be used on a
pointer returned by mparse_result().
man_mparse()
Get the parser used for the current output.
man_node()
Obtain the root node of a successful parse. This may only be used on a
pointer returned by mparse_result().
mchars_alloc()
Allocate an struct mchars * object for translating special characters
into glyphs. See mandoc_char(7) for an overview of special characters.
The object must be freed with mchars_free().
mchars_free()
Free an object created with mchars_alloc().
mchars_num2char()
Convert a character index (e.g., the \N'' escape) into a printable ASCII
character. Returns \0 (the nil character) if the input sequence is mal‐
formed.
mchars_num2uc()
Convert a hexadecimal character index (e.g., the \[uNNNN] escape) into a
Unicode codepoint. Returns \0 (the nil character) if the input sequence
is malformed.
mchars_spec2cp()
Convert a special character into a valid Unicode codepoint. Returns -1
on failure or a non-zero Unicode codepoint on success.
mchars_spec2str()
Convert a special character into an ASCII string. Returns NULL on fail‐
ure.
mdoc_meta()
Obtain the meta-data of a successful parse. This may only be used on a
pointer returned by mparse_result().
mdoc_node()
Obtain the root node of a successful parse. This may only be used on a
pointer returned by mparse_result().
mparse_alloc()
Allocate a parser. The same parser may be used for multiple files so
long as mparse_reset() is called between parses. mparse_free() must be
called to free the memory allocated by this function.
mparse_free()
Free all memory allocated by mparse_alloc().
mparse_getkeep()
Acquire the keep buffer. Must follow a call of mparse_keep().
mparse_keep()
Instruct the parser to retain a copy of its parsed input. This can be
acquired with subsequent mparse_getkeep() calls.
mparse_readfd()
Parse a file or file descriptor. If fd is -1, fname is opened for read‐
ing. Otherwise, fname is assumed to be the name associated with fd.
This may be called multiple times with different parameters; however,
mparse_reset() should be invoked between parses.
mparse_reset()
Reset a parser so that mparse_readfd() may be used again.
mparse_result()
Obtain the result of a parse. Only successful parses (i.e., those where
mparse_readfd() returned less than MANDOCLEVEL_FATAL) should invoke this
function, in which case one of the two pointers will be filled in.
mparse_strerror()
Return a statically-allocated string representation of an error code.
mparse_strlevel()
Return a statically-allocated string representation of a level code.
Variables
man_macronames
The string representation of a man macro as indexed by enum mant.
mdoc_argnames
The string representation of a mdoc macro argument as indexed by enum
mdocargt.
mdoc_macronames
The string representation of a mdoc macro as indexed by enum mdoct.
IMPLEMENTATION NOTES
This section consists of structural documentation for mdoc(7) and man(7)
syntax trees and strings.
Man and Mdoc Strings
Strings may be extracted from mdoc and man meta-data, or from text nodes
(MDOC_TEXT and MAN_TEXT, respectively). These strings have special non-
printing formatting cues embedded in the text itself, as well as roff(7)
escapes preserved from input. Implementing systems will need to handle
both situations to produce human-readable text. In general, strings may
be assumed to consist of 7-bit ASCII characters.
The following non-printing characters may be embedded in text strings:
ASCII_NBRSP
A non-breaking space character.
ASCII_HYPH
A soft hyphen.
Escape characters are also passed verbatim into text strings. An escape
character is a sequence of characters beginning with the backslash (‘\’).
To construct human-readable text, these should be intercepted with
mandoc_escape() and converted with one of mchars_num2char(),
mchars_spec2str(), and so on.
Man Abstract Syntax Tree
This AST is governed by the ontological rules dictated in man(7) and
derives its terminology accordingly.
The AST is composed of struct man_node nodes with element, root and text
types as declared by the type field. Each node also provides its parse
point (the line, sec, and pos fields), its position in the tree (the
parent, child, next and prev fields) and some type-specific data.
The tree itself is arranged according to the following normal form, where
capitalised non-terminals represent nodes.
ROOT ← mnode+
mnode ← ELEMENT | TEXT | BLOCK
BLOCK ← HEAD BODY
HEAD ← mnode*
BODY ← mnode*
ELEMENT ← ELEMENT | TEXT*
TEXT ← [[:ascii:]]*
The only elements capable of nesting other elements are those with next-
lint scope as documented in man(7).
Mdoc Abstract Syntax Tree
This AST is governed by the ontological rules dictated in mdoc(7) and
derives its terminology accordingly. "In-line" elements described in
mdoc(7) are described simply as "elements".
The AST is composed of struct mdoc_node nodes with block, head, body,
element, root and text types as declared by the type field. Each node
also provides its parse point (the line, sec, and pos fields), its posi‐
tion in the tree (the parent, child, nchild, next and prev fields) and
some type-specific data, in particular, for nodes generated from macros,
the generating macro in the tok field.
The tree itself is arranged according to the following normal form, where
capitalised non-terminals represent nodes.
ROOT ← mnode+
mnode ← BLOCK | ELEMENT | TEXT
BLOCK ← HEAD [TEXT] (BODY [TEXT])+ [TAIL [TEXT]]
ELEMENT ← TEXT*
HEAD ← mnode*
BODY ← mnode* [ENDBODY mnode*]
TAIL ← mnode*
TEXT ← [[:ascii:]]*
Of note are the TEXT nodes following the HEAD, BODY and TAIL nodes of the
BLOCK production: these refer to punctuation marks. Furthermore,
although a TEXT node will generally have a non-zero-length string, in the
specific case of ‘.Bd -literal’, an empty line will produce a zero-length
string. Multiple body parts are only found in invocations of ‘Bl
-column’, where a new body introduces a new phrase.
The mdoc(7) syntax tree accommodates for broken block structures as well.
The ENDBODY node is available to end the formatting associated with a
given block before the physical end of that block. It has a non-null end
field, is of the BODY type, has the same tok as the BLOCK it is ending,
and has a pending field pointing to that BLOCK's BODY node. It is an
indirect child of that BODY node and has no children of its own.
An ENDBODY node is generated when a block ends while one of its child
blocks is still open, like in the following example:
.Ao ao
.Bo bo ac
.Ac bc
.Bc end
This example results in the following block structure:
BLOCK Ao
HEAD Ao
BODY Ao
TEXT ao
BLOCK Bo, pending -> Ao
HEAD Bo
BODY Bo
TEXT bo
TEXT ac
ENDBODY Ao, pending -> Ao
TEXT bc
TEXT end
Here, the formatting of the ‘Ao’ block extends from TEXT ao to TEXT ac,
while the formatting of the ‘Bo’ block extends from TEXT bo to TEXT bc.
It renders as follows in -Tascii mode:
<ao [bo ac> bc] end
Support for badly-nested blocks is only provided for backward compatibil‐
ity with some older mdoc(7) implementations. Using badly-nested blocks
is strongly discouraged; for example, the -Thtml and -Txhtml front-ends
to mandoc(1) are unable to render them in any meaningful way. Further‐
more, behaviour when encountering badly-nested blocks is not consistent
across troff implementations, especially when using multiple levels of
badly-nested blocks.
SEE ALSOmandoc(1), eqn(7), man(7), mandoc_char(7), mdoc(7), roff(7), tbl(7)AUTHORS
The mandoc library was written by Kristaps Dzonsons, kristaps@bsd.lv.
BSD January 13, 2012 BSD
